Little groups and Maxwell-type tensors for massive and massless particles
Department of Physics, Middle East Technical
University, Ankara 06531, Turkey
2 Department of Physics, University of Maryland, College Park, MD 20742, USA
Accepted: 30 September 1997
The massive and massless representations of four-vectors and Maxwell-type tensors are constructed as bilinear combinations of SL(2,C)-spinors and are evaluated on a unified description upon adopting the group contraction procedure of O(3)-like little group to E(2)-like little group. Contraction of massive particle representations leads to gauge-dependent vectors as well as the gauge-independent "state vectors" constructed by Weinberg. It is shown that gauge degrees of freedom associated with the translation-like transformations of the E(2)-like little group can be traced to the spinors that undergo spin flips in the infinite-momentum/zero-mass limit.
PACS: 11.30.Cp – Lorentz and Poincaré invariance / 02.20.Qs – General properties, structure, and representation of Lie groups / 03.50.De – Maxwell theory: general mathematical aspects
© EDP Sciences, 1997